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\bibitem{krug2006don't}
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\bibitem{InteractionDesign}
Rogers, Yvonne,
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 Wiley, Chichester, West Sussex, U.K,
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\bibitem{tullis2013measuring}
 Tullis, Tom,
 \emph{Measuring the user experience collecting, analyzing, and presenting usability metrics},
 Elsevier, Amsterdam, Netherlands,
 2nd Edition,
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\end{thebibliography}
